Allows validating that the GitHub milestone is setup to be on a valid release date.

For example, this would confirm that 2021-04-22T22:48:47Z was the Thursday after the 3rd Monday of the Month.

$ java io.spring.releasetrain.CheckMilestoneDueOnMain --dueOn "2021-04-22T22:48:47Z" --expectedDayOfWeek THURSDAY --expectedMondayCount 3

You can integrate with GitHub Actions using something like this

github/workflow/spring-releasetrain-milestones.yml

on:
  milestone:
    types: [created, opened, edited]
env:
  DUE_ON: ${{ github.event.milestone.due_on }}
  TITLE: ${{ github.event.milestone.title }}
jobs:
  spring-releasetrain-checks:
    name: Check DueOn is on a Release Date
    runs-on: ubuntu-latest
    steps:
    - name: Print Milestone Being Checked
      run: echo "Validating DueOn '$DUE_ON' for milestone '$TITLE'"
    - name: Validate DueOn
      if: env.DUE_ON != ''
      run: |
        export TOOL_VERSION=0.1.1
        wget "https://repo.maven.apache.org/maven2/io/spring/releasetrain/spring-release-train-tools/$TOOL_VERSION/spring-release-train-tools-$TOOL_VERSION.jar"
        java -cp "spring-release-train-tools-$TOOL_VERSION.jar" io.spring.releasetrain.CheckMilestoneDueOnMain --dueOn "$DUE_ON" --expectedDayOfWeek THURSDAY --expectedMondayCount 3